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B. G. LAMME. ARMATURE FOR ELECTRIC MACHINES Patented Dec. 13, 1892.

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No. 488,016. Patentd Dec. .13, 1892.

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ARMATU-RE FOR ELECTRIC MACHINES.

No. 488,016. Patented Dec. 13. 1892..

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ARMATURE FOR ELECTRIC MACHINES. No. 488,016. Patented Dec. 13, 1892.

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B. G. LAMMB. ARMATURE FOR ELECTRIC MACHINES.

No. 488,016. Patented Dams, 1892.

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UNTTE STATES BENJAMIN G. LAMME, OF PITTSBURG,

PATENT @TTTQE.

PENNSYLVANIA, ASSIGNOR TO THE PLACE.

ARMATU RE FOR ELE CTRIC MACHINES.

SPECIFICATION forming part of Letters Patent No. 488,016, dated December13, 1892.

Application filed February 8 1892- Serial No. 120.741. (No model.)

To all whom it may concern.-

Be it known that I, BENJAMIN G. LAMME, a citizen of the United States,residing at Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented certain new and useful Improvements inArmatures for Electric Machines and in the Method of Constructing theSame, (Case No. 485,) of which the following is a specification.

The invention relates to the construction of the armatures of electricmachines, and particularly to the method of formin g and applying thecoils to the armature-cores.

Armatures for electric machines have heretofore been built in variousdifferent ways. For instance,they have been constructed with radiatingteeth, between which are wound coils or bobbins of insulated wire, theconvolutions of the bobbins being wound into the spaces between theteeth. In other instances the armature-cores have been constructed witha smooth exterior surface, andcoilswhich have been previously wound havebeen laid upon this surface. In still other instances previously-woundcoils have been placed over individual projecting teeth of thearmaturecores and pressed into place beneath the projections of theteeth. The present invention diifers from any of the plans abovereferred to and may be said to consist generally in forming anarmature-core with numerous radiating teeth and placing previously woundand insulated coils in the spaces between the teeth, each coil spanningseveral teeth, and in bending the ends of the coils down against theends of the armature-core and of underlying coils. In practice it isfrequently desirable to place two of such previously wound and insulatedcoils in each pair of grooves or spaces between the teeth, first placingin one set and then bending their ends down and afterward superposingthe others. In practice it is usually found convenient to bend down theends of each coil immediately upon its insertion-that is to say, eachcoil is fitted to the armature and placed in final positi'on insuccession.

In the accompanying drawings, Figure 1 shows two armature-coils whichhave been core with some of the coils applied. Fig.- 3 is an end view ofthe armature afterall the coils have been applied. Figs. 4 and 5 areplans of the respective sect-ions of a block or coilmold in which thecoils are originally formed. Fig. 6 is an elevation of the two sectionsin position for receiving a coil. Fig. 7 is a longitudinal section, andFig. 8 is a side elevation, of the block with coils applied. Fig. 9 is across-sectiou,and Fig. 10 an end view, of the block with coils woundthereon.

Referring to the figures, a description will first be given of the planof winding or forming the coils. The forming-block is made in two partsA A These two blocks are bolted together or suitably fastened in anyconvenient manner-as, for instance, by a bolt a, passing through fromone block to the other and keyed, as indicated at a. Aplate a may besecurely fastened to one of the plates A and this plate is provided witha stern ed, by means of which it may be held in a lathe or supported inany suitable manner for convenience in winding. By placing the stem inthe lathe the mold may be revolved and the wire laid into the suitablereceiving groove B, which extends around the periphery of the mold. Thegeneral shape and form of the groove is illustrated in the drawings. Itmay be generally stated of it that it is narrow and deep at the two endsof the mold and at the two sides it is shallow and of a widthapproximately equivalent to the depth upon the two ends. Moreover, thegroove is further so formed that a twist is given to it at each end, sothat the strand of wire which is toward the left hand upon one side ofthe mold falls upon the right hand upon the other side of the mold. Thisconstruction provides that the two terminals of a coil when placed uponthe armature will both be upon the outer side instead of one of thembeing at the bottom of the groove or space within which it is laid.

In using the mold after it has been suitably placed together and mountedupon a lathe two sockets of insulating material-such, for instance, asfuller-boards, which have been previously bent into a U shape, asillustrated at D-are laid in the grooves in the opposite sides of themold. The sides of these sockets project outward a sufiicient distanceto permit of their being bent down over the coils after the wires havebeen laid therein. One end of a wire 0 is then fastened to apin c andpassed along a groove 0' until it reaches the edge of the mold. It isthen laid against the bottom of the insulating-plate toward the lefthand, Fig. 10. Themold is revolved and the wire is laid along the lengthand across the end and then appears upon the opposite edge of theopposite side of the mold in the position indicated by the strand marked0 Figs. 9 and 10. This strand is then passed along the end of the moldand lies at the bottom of the groove until it reaches the first side ofthe mold, where it appears in the position indicated by the strand 0Fig. 10. The wire is continuously applied in the manner above describeduntil the final end appears in the position marked 0 This constructionintroduces a half-turn in the coil at. each end. The sides oftheinsulatingsockets are then turned down upon the surface of the wireand glued in position, and temporary clamps cl may be employed forholding them in position until dried. Thekey a, is then removed,theblocks separated, and the coil is slipped off from the mold. It shouldbe observed that the lefthand edgethat is to say, the first edge formedon one side of the coil-is approximately in the same plane as theright-hand edge of the opposite side of the coil. This clearly appearsin Fig. 9that is to say, the two sides of the coil will fall uponopposite sides of a plane which is made perpendicular to the axis of thecoil. Furthermore, the two sides converge at an angle which would causeplanes projected in the direction of the planes of the sides of thecoils to meet at a distance from the coils approximately equal to theradius of the armature-core to which they are to be applied. In this Waythe coils are in proper form to be readily fitted between thearmature-teeth. After the coils have been suitably wound the respectiveends are taped, as indicated in the drawings, and forconvenience inusing the coils it is found desirable to tape them withdifferent-colored tapes, so that corresponding ends may always bedistinguished. The coils may then be immersed in a suitable insulatingmaterial, such as varnish or shellac, and afterward the entire coil isthoroughly taped, as indicated in Figs. 1 and 2. They are then ready tobe applied to the armature-core.

The armature-core E is made with narrow radiating teeth 6, leavingintervening spaces 6. This core may be of any suitable character and maywith advantage be made of thin plates built up in a manner wellunderstood. The coils, having been prepared in the manner described, arepressed into the grooves e, the

two sides spanning a predetermined number of teeth. The ends are thenpressed down against the ends of the armaturecore and successive coilsare fitted against each other in the general manner illustrated in Figs.2 and 3. By this system each coil is fitted to its place as it is put onand will not fit in another position without slightly-different bends atthe end. In other words, all coils are first made in one general shapeand each coil is fitted to the armature when placed in position and itsends bent to conform to the most convenient position against theunderlying coils.

The twist or half-turn in the ends of the coil is important, asitrenders it possible to readily bend the ends of the coil down into placeagainst the end of the armature. eral wires taped into an ordinary flatcoil will not allow of much bending without buckling the coil. The twistin the present instance does away with this to a great extent. Thestrand of wire at the upper or outer edge of one side of a coil lies atthe lower edge of the other side. The second wire from the top on oneside is the second from the bottom on the other side, and so on. Inbending down the coil over the end of the armature the wires, being ofthe same length approximately, adjust themselves to the bend by merelytwisting the coil a little more or less and there is no sliding orshifting of wires upon each other. This twist also permits the ends ofeach coil to lie flat against the underlying coil, thus requiring lessspace at the end of the armature than it they stood out edgewise.

By reference to Fig. 2 it will be seen that the bending down of the endsof the coils produces two rolls or bunches at the end of the armature,an open space being left at each side between them, as shown at p, forinstance. The only points in the armature where any considerabledifference of potential occurs is where the two halves thus formed meet,and for additional security a layer of insulating material 1) may beinserted between the two sections at these points. It should be added,however, that the armature is wound with as many sets or divisions ofcoils as there are poles to the armature. In a four-pole armature, forexample, there will be four divisions of the armature-coils. This may bemost conveniently accomplished by using two layers of coils, each layerarranged in two sections, two coils being placed in each set of spacesbetween the teeth. In order that the ends of the coils may suitablyshape themselves at the ends of the armature-core when they are bentdown, it is desirable that the outer shall be slightly longer than theinner ones, as they have to lap over the inner ones at the ends of thearmature. hen two layers of coils are thus employed, they are so appliedthat the two rolls formed at the ends by the outer coils are above thespaces between the two rolls formed by the inner coils, and as a resultthe ends of the armature present a neat uniform appearance and amechanical 1 a tist.

Sevi balance and the end wires are not massed together, as in ordinaryconstructions, and this afiords better ventilation.

For the purpose of thoroughly insulating the inner from the outer layerof coils a cap or sheet f of insulating material may be placed over eachend of the armature after the first lay-er is applied. By thus windingin sets, however, and in two layers wires having high difference ofpotential are not brought close together except at the points where thesets meet, and these points, as already stated, are specially insulated.The adjacent coils at the ends are connected with adjacent commutatorbars. The bending down and fitting of each coil in place gives it ashape which helps to hold it in its slots against centrifugal forces,thus making it possible to dispense with bands in certain cases. Whenthe winding is finished, all the coils, except a few at the end of eachupper set, are rigidly held in place in the rolls, thus preventing anyvibration or movement among them. Thelast few coils may be fittedespecially tightly in the slots, thus giving them the sufficientsupport. An armature constructed in this manner possesses severaladvantages over those in which the coils are wound upon the surface.Thus, for example, in a surface-wound armature subjected to great stressor torque the wires are liable to be shifted by reason of the strainexerted upon them, and if not shifted bodily they have a constanttendency to move slightly to and fro, thus producing an abrasion and aninjury to the insulation.

By winding the coils in formers and insulating them thoroughly by thefuller-board and tape all danger of making accidental electricalconnection with the core is avoided and the coils may be driven tightlyinto the spaces between the teeth, and thus held rigidly without dangerof shifting or abrasion. This insulation cannot be obtained by windingthe coils by hand into the spaces between the teeth. Neither can theresult of bringing the two ends of the wire upon the outside be securedby laying the separate convolutions in the spaces in the armature-core,for the first end of the coil would lie at the bottom of one slot, whilethelast end would be at the outer edge of its slot. This is a matter ofconsiderable importance in practical work, for if either end of the wirewere at the bottom of I the slot it would necessitate an additional bendin the strand of wire in order to bring it out to the commutator. Theeconomy of construction, moreover,'is another advantage of importance,the winding of the coils by machine or in formers being much lessexpensive than the construction which requries the laying of theindividual wires into the openings between the teeth.

Instead of having the last end of the coil brought out at the oppositeside from the first end it may be carried across into proximity to thefirst end, as indicated by dotted lines in Fig. 1. The positiondesirable in any given instance will depend upon the form and purpose ofthe armature in which the coil is to be used.

I claim as my invention 1. The combination, with a drum-armature corehaving radiating teeth, of separatelywound coils placed within thespaces between the teeth, each coil spanning several teeth.

2. The combination, with adru m-armature core having radiating teeth, ofcoils of insulated wire placed within the spaces between the teeth, eachcoil spanning several teeth, said coils being separately wound andseparately insulated.

3. The combination of a toothed armaturecore and machine-wound coilsplaced in slots between the teeth of said core, each of which coilsspans several of the teeth.

4:. A coil for the armature of an electric machine, having its two sideslying in converging planes and its two ends each containing a half-turn,whereby the upper wire upon one side becomes the under wire upon theother side.

5. An armature for an electric machine, consisting of a toothed core andtwo series of coils placed within the spaces between the teeth, eachcoil of each of said series being separately wound and separatelyinsulated.

6. An armature for electric machines, consisting of a toothed core,aseries of insulated armature-coils laid in the spaces between the teethand each coil spanning two or more teeth, and a second series ofinsulated coils laid in the spaces upon the first series.

7. An armature for electric machines, consisting of a toothedarmature-core, a series of previously-wound armature-coils laid inspaces between teeth and each coil spanning several teeth and having itsends afterward bent down upon the ends of the armaturecore, and a secondseries of previously-wound coils laid above the first-named and havingtheir ends afterward bent down against the end of the armature-core andthe underlying coils.

8. In an armature for electric machines, two sets of separately woundand insulated armature-coils, one set being placed radially over theother, the length of the coils of one set being greater than that of thecoils of the other set.

9. .An armature-coil consisting of convolutions of insulated wire and alongitudinal insulating-sheath applied to two sides of said coil.

10. The combination, with a toothed armature-core, of coils of wire laidthrough the teeth and pressed down upon the ends of the core, each coilbinding in position the previous coils, substantially as described.

11. In an armature for electric machines, the combination, with atoothed armaturecore, of previously wound and insulated coils laid.within the spaces between the teeth and each coil spanning severalteeth, the ends of it seems the coils being pressed downagainst the endsof the armature-core and forming, two or more rolls or projections ateach end of the core, substantially as described.

12. In an armature for electric machines, a toothed armature-core andtwo layers of armatureeoils, each layer divided into sections, all ofthe coils havingtheir ends pressed down toward the respective ends ofthe armature- [0 core and the ends of each section forming a roll orprojection, the rolls or projections formed by one layer of coils comingbetween the rolls or projections formed by the other layer of coils.

13. An armature-core for electric machines \Vitnesses:

h-IARLES A. TERRY, JAMES WM. SMITH.

